Different substrates get oxidised during respiration. How does respiratory quotient (RQ) indicate which type of substrate i.e. carbohydrate, fat or protein is getting oxidised ?
R. Q = A / B
What do A and B stand for ?
What type of substrates have RQ of 1,<1, >1?

i) The ratio of the volume of CO₂ evolved to the volume of O₂ consumed in respiration is called the respiratory quotient (RQ)
RQ = A / B
A stands for volume of CO₂ evolved
B stands for volume of O₂ consumed
ii) When carbohydrates are used as substrates, the RQ is 1. When fats and proteins are respiratory substrates, the RQ is less than 1 and when organic acids are respiratory substrates, the RQ is more than 1.
Thus RQ indicates the type of substrate used during respiration.